The hunky Hollywood actor took to Twitter on American Independence Day to announce his new wife is expecting their third child.
He tweeted: "Happy birthday America, more good news, Camila and I are expecting our 3rd child."
The glamourous couple, who already have two children together, got married in a intimate ceremony last month.
The 42-year-old tied the knot with the gorgeous Brazilian at their sprawling family home in Austin, Texas.
[Related story: Matthew McConaughey & Camilla Alves marry in private ceremony]
Matthew had popped the question back in December with a three-stone diamond engagement ring.
The pair have two kids - four-year-old Levi and Vida, who is two.
Matthew is set to hit UK shores next week for the premiere of his new film 'Magic Mike', in which he plays the manager of a strip club.
The pair stepped out together on the red carpet last week at the LA premiere of the film.
Drop-dead-gorgeous Camilla Alves wore a thigh-skimming black and blue sequined dress but showed no sign yet of a baby bump.